Open DDD File
DDD files could be used in multiple different applications.
Adobe Distiller
DDD files are directly associated with Adobe Distiller software, which is used to manage PDF files.
Adobe Distiller uses the DDD files to generate PDF documents on the fly, and these are in turn sent directly to the print server.
GLBasic 3D
In this case, the DDD files are used by GLBasic, an application used to develop multiplatform software with the BASIC programming language, to save the vertices of a 3D object programmed in said program.
Alpha Five
In this application, DDD files are dictionary files created by Alpha Five, an IDE designed to develop web, desktop and mobile applications.
Contains elements of explorations, reports, saved operations, letters, and form layouts.
Basically, DDD files are equivalent to a database.
To open and work with a DDD file, you must have one of the following software packages, but not before checking the format of the file: